Controlling crystal precipitation in magnesium aluminosilicate glasses via thermoelectric coupling

Abstract

MgO–Al2O3–SiO2 (MAS) the basic glass was prepared by the traditional melt-quenching method, whereas the glass-ceramics was produced by subjecting the glass to thermoelectric coupling treatment. The MAS glass-ceramics were characterized by FTIR, XPS, and SEM. Clearly, the extension of the heat-treatment time did not change the crystal grains number in the absence of an electric field. However, with the electric-field voltage increase,the crystal grains number in the MAS glass-ceramics gradually increased when the electric-field voltage became steady at 1200 V. At high temperatures, Ti4+ participates in the silicon-oxygen network with four coordinations and produces good miscibility with the melt. By the introduction of electric field into the glass, a high amount of titanium transforms from a titanium-oxide tetrahedron to a titanium-oxide octahedron. Titanium was separated from the silicon–oxygen network framework to form a crystal nucleus and promote crystal growth. This study provides insights into the relationship between electric-field and glass-ceramics nucleation.